OSPF and IS-IS are two robust and scalable link-state protocols that are used in many networks throughout the Internet. They are based on industry standards, meaning they are available and interoperable with all major vendors’ routing equipment. These protocols are also arguably among the earliest forms of high availability. Sure, dynamic routing protocols were designed to ease the administrative burden as networks grow, but the real power is in their ability to dynamically detect an issue in a network and to recover from that issue by rerouting traffic along an alternate path. This is high availability in action!
Since OSPF and IS-IS were first implemented in commercial routers, back in the early 1990s, there has been a great deal of debate over which protocol is superior. Today, many of each protocol’s unique features have been implemented by the other, making both protocols very similar in feature set and functionality. That being said, there are still aspects of each that can be considered advantageous or disadvantageous, depending on the situation and environment.
OSPF was developed by the Internet Engineering Task Force (IETF) as a reliable routing protocol that runs directly on IP. It was designed specifically with IP networks in mind, and has found a home largely in medium-size to large enterprise networks, although it is used by several service providers as well.
JUNOS Software supports the full range of OSPF features you would expect to ...